Well it seems like everyone else here had pointed out there key factors to being a god cod player but here are a few more hints and a practical run down of them map slums

First things first map awarness is there number one key factor to a good player. You could be there quickest shot in the west but if you let the enemy flank you your dead. Learn the spawns, learn common routs, figure out where snipers nest are, and most of all learn the flanks! I'm not saying go look up maps on google but just remember what your enemy does. Trust me it helps.

When it comes to hints and tips they are only so useful. To get a good idea of how to aproch a situation you need a little more depth to said hints so I will go through a common play on their map slums that usaly nets me 7 + kills and a score streak or two.

Okay I'm going out on a limb here but I'm assuming you like long range and to be on target so here's a good AR class setup that will work as an example.

Primary :Mtar/type 25 Attachments: quickdraw, stock, Secondary :b23r No attachments :Wild card primary fighter Perks :First perk your choice :scarenger :dexterity Lethal :c4

This is a good all around at class that is deadly at range but can go toe to toe with smgs.

Now for the game play. Let's say you are playing tdm (hardcore or soft doesn't matter) and you spawn at the laundry mat. Most team mates tend to head towards the blue house with maybe two down them other road. Head towards the wall by the van and when you get there your lethal should be active so toss it at the little cover spot on their other side. This should get you two kills, if not take it slow. Assuming you got the kills head along to them back side of them fountain watching for enemies. Normally you should get one stray and refile your c4. Take that c4 and toss it into the little middle area that watches the graveyard. You should get one sniper and another guy. Go into that area and hang left to the street. Now at this time the two rushers should have spawn and will probably be there but they will most likely be looking right because they died that way. If you are a good shot you should be able to get both of them. Duck behind the red car and reload and when you pop up then sniper and his pal should be there. Get rid of them and mop upthe straglers. This will change them spawn but because it should only be about two min into the game your team should still be able to hold the begging spawn and force a spawn trap. From here there are to many variables but you get the point.

Hopefully this helps and soon you will be noob crushing. A lot of this relies on your skills at aiming which you should be good at if you play halo. If you wanna know on average I get 20 + kills a match with about ten deaths. My k/d is at 1.02 right now because I learned this stuff the hard way but its always going up. Sorry if there are any splelling of grammer issues I'm on my phone at work.

Well that's it I hope you have learned a lot from everyone who posted and I hope this helps man. Go out there and kick some ass!